<!DOCTYPE html>
<html>

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script> </head>
    <style>
    img{
        width:10%;
    }
    </style>
<body>
    <div class="container">
        <img src="./download.jpg">
        <img src="./download.jpg" class="rounded">
        <img src="./download.jpg" class="rounded-circle">
        <img src="./download.jpg" class="img-thumbnail"> 
    </div>
</body>

</html>